Add description of pwm[1-4]_start_output, pwm[1-4]_step_output,
pwm[1-4]_stop_output, and pwm[1-4]_max_output attributes to driver
documentation.
Signed-off-by: NGuenter Roeck <guenter.roeck@ericsson.com>
Acked-by: NJean Delvare <khali@linux-fr.org>